Muffler



R. w. COMPO 2,113,828 7 April 12, 1938.

MUFFLER Filed May 18, 1936 as 9 1g 12% 15 0000 o ooooo ooo oo Patented Apr. 12, 1938 UNITED STATES PATENT OFFICE 1 Claim.

My invention has for its object to provide a mufller having a plurality of shells located one within the other to permit progressive expansion and distribution of the hot gases, and at the same time to permit progressive lowering of the temperature coincident with the reduction in pressure, to eliminate the pulsatory sound produced by the explosive exhaust of engines. The invention particularly provides means for progressively sub-dividing the exhaust gases by directing the gases through holes of small diameter formed in sheet metal parts to dissipate the expansive force of the gases as they are exhausted, which progressively lessens the rate of flow and an emission of the gases from the outlet pipe of the mufiler at substantially a uniform rate.

The invention may be contained in mufflers that vary in their forms of construction, and to illustrate a practical application of the invention, I have selected a mufiler containing the invention and shall describe the mufiler selected hereinafter. The particular muffler referred to is shown in the accompanying drawing.

Fig. 1 is a view of a longitudinal section of the mufiler. Fig. 2 illustrates a transverse section of the mufiler shown in Fig. 1. Fig. 3 is a broken View of the muffler to illustrate the arrangement of the openings in the walls of the inner shells of the mufiler.

The mufiler shown in the drawing comprises an outer casing I having a pair of flanged heads 2. The flanges 3 of the heads are flared as at 4 and united with the flared end edges 6 of the casing by welding. The heads 2 are provided with flanged plates 1. The flanges 8 of the plates 1 fit Within the inner surfaces of the flanges 3 of the heads 2 and may be, if desired, spot welded or otherwise secured to the flanges 3. The heads 2 and the plates I are provided with openings 9 and II that are located in alignment, and edge parts of the openings are turned from the planes of the surfaces of the heads 2 and plates 1 to form flanges l2 and I3. The intake pipe l4 and the exhaust pipe l6 fit the interior surfaces of the flanges l2 and I3 and connect the exhaust pipe of the engine and the tail pipe of the muffler with the interior of the mufller.

A pair of partitioning plates l1 and I8 are located in proximity to the heads 2 and form the inlet chamber l9 and the exhaust chamber 2| with which the inlet pipes M and the exhaust pipes l6, respectively, communicate. The plates l1 and I8 are provided with the flanges 22 and 23 that fit the interior surface of the casing I.

The plate I! is provided with a circular, centrally disposed raised portion 24 and also a central raised portion 25 located within the area of the raised portion 24. These portions are struck up from the sheet metal of which the plate I! is formed to produce the slightly sloping, conical or substantially cylindrically formed portions 26 and 21. The plate I8 is also provided with a centrally disposed raised portion 28. The raised portion 28 is struck up from the sheet metal of 0 which the plate 18 is formed to produce the slightly sloping, conical or substantially cylindrical surfaces 29 and 3|. A pair of shells 32 and 33 are coaxially disposed with reference to the casing I and have diameters such that their in- 15 ner surfaces at one end of each of the shells fit the surfaces 26 and 2'! of the plate l1, and the other ends of the shells fit the edge parts or surfaces 29 and 3! of the plate l8. The plate H has a plurality of openings 34 located in the marginal region of the plate and connect the inlet cham- 20 her IS with the chamber 35 formed intermediate the outer shell 32 and the wall of the casing l. The plate I8 is provided with a centrally disposed opening 31 into which one end of the shell 33 extends and communicates with the exhaust chamber 2!. The shells may be secured to the surfaces 26, 21, 21, and 3| by spot welding or otherwise to secure them in their relative positions.

Each of the shells 32 and 33 are provided with rows of openings 38 and 39 formed in opposite side portions thereof. The rows of openings of each shell are separated by portions of the shells that are formed solid, that is without openings, 35 such as the portions M and 42. The solid portions 4| and 42 are located in radial alignment with respect to the common axis of the shells and the casing with the openings of the other of the shells. Preferably each shell is provided with two relatively closely disposed rows of openings in each of the said side portions. Thus, the exhaust gases that enter the chamber 36 located intermediate the casing and the outer shell 32 are directed over the entire inner surface of the 45 casing l and are materially cooled by reason of the fact that the atmospheric air makes contact with the exterior of the drum l. The rows of holes 38 being located in opposite side portions of the shell 32, the gases which enter through the openings 34 are distributed over the entire space intermediate the casing i and the shell 32 and thus the temperature of the gases is greatly reduced by reason of the retention of the gases Within the chamber 36 and in contact with the inner surface of the shell. Eventually the gases escape through the openings 38 of the shell 32 into the chamber formed between the inner and the outer of the shells 32 and 33. The solid portions 42 of the shell 33 being located in radial alignment with the openings 38, the gases are further retarded and bafiled and thus are caused to fill the chamber formed intermediate the inner and the outer shells, as relatively small portions continue to escape through the openings 39 formed in the side portions of the inner shell 33. The exhaust gases then flow with a relative steady stream through the end of the shell 33 into the exhaust chamber 2| and escape through the ex haust pipe l6 that is connected to the tail pipe of the conveyance or vehicle.

Preferably the openings formed in the plate I! and the inner and outer shells are relatively small, such as about one-eighth inch in diameter, which causes marked retardation and decrease in the flow of the gases and enables expansion and reduction in temperature, not only by the cooling area of the inner surface of the drum, but also by reason of the expansion of the gases. This results in a substantially continuous exhaust of the gases of the engine from the muliler. The explosive sound of the repeated exhausts is thus eliminated.

I claim:

In a muffler, a casing having flanged end parts, flanged heads secured to the said end parts of the casing, flanged plate extending across and fitting the flanged parts of the heads, each plate and its associated head having aligned openings, the heads and the plates having flanged parts located at the edges of the openings and inlet and exhaust pipes interfltting the flanged parts about the openings and extending from the exterior into the interior of the muffler, and a baille means located intermediate the openings for delaying the movement of the exhaust gases from the inlet pipe to the exhaust pipe.

ROBERT W. COMPO. 

